1. FIELD OF THE INVENTION
The present invention generally relates to seismic exploration and more particularly to a disposable point detachably mounted on the lower end of a vertically movable hole forming elongated member and having an explosive charge mounted therein in order for the disposable point to remain in the bottom of a hole formed by the elongated member and point when they are forced into a subsurface formation which is to be seismically explored.
2. DESCRIPTION OF THE PRIOR ART
As is well known, seismic exploration of underground formations is conducted by positioning a plurality of explosive seismic charges below ground level at a designated depth and in a designated pattern with these charges being subsequently detonated to produce seismograph recordings which can be analyzed to determine the character of the underground formation including whether the underground strata includes potentially recoverable oil or gas deposits and the like. Various devices have been provided to form vertical bores or holes in the earth's surface in which seismic charges are placed and detonated. The following U.S. patents relate to this field of endeavor and include devices for forming vertically extending holes in the surface of the earth. 3,394,766 3,920,083 4,471,669 4,553,443 4,819,740
The above patents do not disclose a disposable point having an explosive charge therein which is detachably mounted on the lower end of an elongated member which forms a hole or bore in the earth with the point and explosive charge remaining at the bottom of the hole when the elongated member is retracted from the hole.